Peel the chayotes, remove the seeds and
cut into strips. If using courgettes, cut into 2 inch strips. Grind the
fresh red chilies, onion, sliced galangal, sliced lemon grass and the
fresh turmeric to a paste in a food processor or with a pestle and
mortar. Add the water to the paste mixture, with a squeeze of lemon
juice and salt to taste.

Pour into a
pan. Add the top of the lemon grass stem. Bring to the boil and cook for
1-2 minutes. Add the chayote or courgette pieces and cook for 2 minutes.
Stir in the coconut milk. Taste and adjust the seasoning. Stir in the
prawns and cook gently for 2-3 minutes. Remove the lemon grass stem.
Garnish with shreds or chili, if using, and serve with rice.